[ntp:questions] NIST vs. pool.ntp.org ?

Richard B. Gilbert rgilbert88 at comcast.net
Fri Mar 29 20:27:34 UTC 2013

On 3/28/2013 8:22 AM, Magnus Danielson wrote:
> On 03/27/2013 10:45 PM, David Woolley wrote:
>> Robert Scott wrote:
>>> I am confused about the proper usage of pool.ntp.org and NIST.
>>> pool.ntp.org seems to be a collection of private sector time servers
>>> offered for all to use, but with registration expected for regular
>> The pool system has no provision for enforcing registration. It wouldn't
>> make sense to hand out a random server address if most of them then
>> refused to serve you because you hadn't registered.
>>> users. And NIST has a government run set of time servers. Neither
>>> group (NIST or pool.ntp.org) seems to include or referece the other.
>> I would hope all the pool servers ultimately reference their national
>> equivalent of NIST and therefore what becomes, after the fact, UTC.
>> I think you will find that Navstar (GPS) and WWV times are traceable to
>> NIST.
> Yes and no.
> GPS is traceable to USNO. USNO and NIST have traceability between each
> other within the BIPM framework.
>> MSF times are traceable to NPL.
> NPL is traceable to both USNO and NIST within the BIPM framework.
>>> Are they in competition? Who normally uses the NIST servers and who
>>> uses pool.ntp.org?
>> The open NIST servers are heavily overloaded, so probably don't serve
>> the highest quality time, but they are likely to be around for a long
>> time.
> I would setup a local server under your control. It will help both from
> debugging and noise perspective.
> Cheers,
> Magnus

If you really want the best time, consider a GPS Timing Receiver.  The 
GPS Timing Receiver should give you a "tick" that's +- 50 nanoseconds. 
If you need better, you will need your own "atomic clock"!  It also 
gives you the "value" of that tick; e.g. 4:03:32. . . . .

Many of us here do not actually need +/- 50 nanoseconds.  What I DID 
want was to have all the clocks in all the "clocks" in the house in 
agreement! It's not perfect but it's close enough. . . .

More information about the questions mailing list